Blast furnace top



. F. JUENGLING BLAST FURNACE TOP Nov. i9, 1935.

Filed May l5. 1935 3 Sheets-Sheet 1 NGV, E9, 1935. K. F, JUENVGUNG 2,021,555

BLAST FURNACE TOP 3 Sheets-Sheet 2 Filed May 15, 1933 m1. E9? 1935. K. F. JUENGUNG BLAST FURNACE TOP4 Filed May 15, 1953 5 Sheets-Sheet 3 Patented Nov. 19, 1935 iJNiTr-:DA STATES PATENT orricrs.I

8 Claims.

My invention particularly relates to improvements in blast furnace tops which effect a more uniformq flow of gas through the furnace and away from the latter, which reduce the losses of flue dust from the furnace, and which provide a furnace top cooler in operation than the usual constructions of furnace tops. Other advantages of the improved construction will clearly appear in the detail description of' the invention hereinafter presented.

The annexed drawings and the following description set forth in detail certain means embodying the principle of my improvements in furnace tops, such means constituting, however, but a few of the various forms by which the principle of the invention may be illustrated.

In said annexed drawings:

Figure 1 is a central vertical section of the hearth, bosh, and shaft sections of a standard design of blast furnace provided with my improved -top construction, together with associated small and large charging bells, their cooperating hoppers, gas seal, etc.;

Figure 2 is an enlarged View of the top and associated elements .shown in Figure l, the View being taken in the planes indicated by the line 2 2, Figure 3;

Figure 3 is a plan section, taken in the planes indicated by the line 3-3, Figure 2;

Figure 4 is a view similar to Figure 2 of a modified form of top construction;` and Figure 5 is a View similar to Figures 2 and 4 of a second modified form of top construction.

Referring to the accompanying drawings in which the same reference numbers refer to the same elements in the several views, a furnace shaft I, Figure 1, comprising a shell I and lining I2 therefor, is shown, which is of the well-known frusto-conical design and has the bosh section 2 and the hearth section 3, to the latter of which the gas to support combustion is furnished by the tuyres A. The shaft I is supported upon the base 5 by means of the vertical columns B.

The lining I2 of the shaft I is inwardly inclined to the level of a horizontal plane 1 whence it is extended vertically upwardly to the level of a plane 8, which latter plane is above the stock line 9 and is substantially coincident with the plane of the lower end of the large lower charging bell I2, when the latter is in its charging position, shown in dot-and-dash lines, Figure 1. From the plane 8 the shaft I sharply flares outwardly and upwardly, as indicated by the surface I0. Having its inner surface in a plane substantially with the plane of the surface I0, and hence also materially flared outwardly and upwardly, is a shaft section II which extends materially above the bottom of the bell I2, is suitably secured to the shaft I, and is reinforced by braces I I secured to its under surfaces and to the outer surface of the 5 shaft I. The shaft section II provides an enlarged chamber 22 of constantly increasing crosssectional dimensions from about the plane of the bottom of the hopper I8 to the top of the shaft section I I. This chamber 22 provides a free and 10 enlarged area for the passage of gas. The top of the shaft section I I provides a support for a roof I3 for the furnace shaft, which roof I3 is at and provided with spacedgas offtakes I4 whose axes are vertical and which communicate with respec- 15 tive downcomers 35.

The detailed construction of the roof I3 comprises spaced connected upper and lower plates I5 and I6, respectively, which are reinforced by a circular girder I1 and by a series of radial gird- 20 ers I9 secured to and extended outwardly from the circular girder I1, the roof I3 thus formed resting upon the outer edge of the shaft section I I. Thus the load consisting of the large charging hopper I8, large bell I2, gas seal 34 and other 25 usual features supported by a furnace top is transmitted from the circular girder Il to the outside edge of the furnace shaft section I I. The upper plates I5 are fastened upon the radial girders I9, as clearly indicated in Figure 3, and the 30 lower plates I6 have inner extensions I6 upon which rests a circular angle 33 which in turn supports a circular channel 29 upon which rests the flange I8 of the hopper I8. Secured to the under. surface of the plate I6 is insulation 20 which pro- 35 tects the plate I6 from the heat of the furnace and which is held in place by means of light plates 2I secured to the plate I6 by bolts 3|. The outer edges of the plates I6 and 2I are secured together and are fastened to the outer face of the 40 shaft II. Suitable transverse angular cross braces 32 as needed are secured to the radial girders I9.

In a furnace of the general construction described, the furnace gases which are produced by 45 the smelting operation of the furnace pass up through the stock column, attack and reduce the ore, and then pass out from the shaft I at the plane 3. These gases travel at high velocity and carry a material amount of dust consisting of 50 minute particles of fine ore, coke and limestone, of which the greater per cent is ore. Certain disadvantages are occasioned by such operations, of which the two more important are that the high velocity of the gases induces channeling through the furnace burden and a consequent non-unform flow of gas through the furnace and, also, the ue dust carried by the gas, particularly the ore dust, constitutes a direct and large loss of material.

However, by the top construction which I have shown and described, the gases upon passing the plane 8 quickly and materially expand within the enlarged chamber 22 formed by the shaft section II, and hence their velocity is materially decreased. The mushrooming effect upon the gas ow and the consequent drop in gas velocity effect a deposition upon the wall of the shell section II of a considerable portion of the dust carried by the gas. The dust so deposited gradually slides back into the furnace. Thus is effected a direct saving of valuable material heretofore lost.

An additional advantage consequent upon the saving of flue dust is that much of the trouble and expense occasioned by the subsequent disposal of the dust through dust catchers, gas cleaners, and similar apparatus is obviated. Thus the gas is cleaned and prepared for its customary use in boilers and hot blast stoves more easily and economically. A saving in fuel is also effected.

Furthermore, by reason of the enlarged roof I3, a greater surface than usual is provided for radiation of the heat of the gases, so that the consequent reduction in the temperature of the gases results in a correspondingly small volume thereof and thus effects a still further reduction in their. velocity.

I direct particular attention to certain features of my invention which cooperate to effect the advantages noted. It is desirable that an even and uniform'flow of outgoing gases at a comparatively low velocity take place through the several gas oiftakes I4. The volume of the gases in my improved construction is largest in the plane where they enter the offtakes I4. This is quite important as tending to induce a uniform flow of gases through the furnace burden which tends to materially `reduce any -channeling through the burden by the gases. My construction provides for such uniformilow of gases through the olftakes I4 through the medium of the materially enlarged gas expansion chamber 22. In this chamber 22 the gas pressure becomes equalized and -the velocity materially reduced before the gases reach the offtakes. Furthermore, the slowing down of the velocity of the gases issuing froml the furnace reduces the pull of these gases upon oncoming gas and hence reduces the channeling effect throughout the furnace burden and produces more uniform flow of the gas through the burden and smoother furnace operation. The comparatively low velocity also resultsin a deposition of a material portion of the flue dust.

Inasmuch .as the wall of the shaft section II flares outwardly continuously to the extreme top of the furnace, or is of greatest diameter adjacent said top, I am able to provide the furnace with a roof which is flat and hence provides convenient means for positioning the gas offtakes I4 in the roof with their axes vertical, or parallel with the axis of the shaft I. Such a disposition of the gas offtakes I4 assists in uniform flow of the gas through such offtakes and leaves an uninterrupted wall surface upon the shaft section II where a material part of the dust may deposit and slide back into the furnace.

The shaft section II, Figure 2, is so arranged relative to the large lower bell I 2 and its cooperating hopper I8 that the chamber`22 continuously increases upwardly in a cross-sectional area above the level of the bottom of the bell I2 and hopper I 8. Thus the stock line 8 which is effected by the discharge of the burden from the large bell I2 in its lowered position indicated in dot-and-dash lines, Figure 3, is ,always below the bottom of the enlarged chamber 22 which thus can operate to its full capacity to permit the expansion and slow ing down of the gases.

Also, such relative arrangement of the shaft 10 section II and the bell I2 permits the burden to fall from the bell I2 into the furnace shaft and .notl upon the wall of the expansion chamber', and

thus a satisfactory distribution in the furnace of the different portions of the burden is effected.

In the forms of construction shown in Figures 4 and 5, the expansion chamber 22 does not continuously increase in cross-sectional area from bottom to top; however, its cross-sectional area at the top is as large as, or larger than, the cross- 20 sectional area in any other horizontal plane, so that such an expansion chamber presents the ,advantages hereinbefore set forth.

In the form of construction shown in Figure 4, a vertical shaft section 23 is provided upon which 25 a at roof 25 is mounted. This section 23 is an upward extension of a shaft section 24 which is upwardly and outwardly flared and is mounted upon the main shaft proper I and has its inner surface in the plane of the outwardly flared top I0 of the shaft I. The exp-ansion chamber 22 is formed by the shaft sections 23 and 24. 'Ihe section 23 is provided with spaced doors 26 by means of which the dust deposited upon the section 24 can be pushed into the furnace. In this form of construction, lI connect the gas ofitakes 21 with the vertically-extended shaft section 23.

In the form of construction shown in Figure 5, I have formed an expansion chamber 22 by means of a shaft section 28 which is extended outwardly 40 in a horizontal plane .at right angles to the axis of the main shaft portion I and at substantially the level of the bottom of the hopper I8, and then is extended vertically. The dust deposited during operation on the shaft section 2a is indicated by 45 3I. Upon the top of the Vertical part of the shaft section 28 the flat roof 38 is supported. The roof 3 in this form of construction is intersected by the spaced gas oiftakes I4 in a manner similar to that shown in the construction of Figures 1, 2, and 3. Clean-out doors 38 are provided in the vertical extension of the shaft section 28.

In .all forms of construction the upper plates I5 of the roof can be extended where desired to form a free and level working platform 3B. 55

What I claim is:

1. A blast furnace construction comprising a furnace shaft, a hopper and a bell control therefor for charging into said shaft, the latter having -a top portion providing a chamber of constantly upwardly increasing cross-sectional dimensions above the level of the bottom of the hopper, the diameter of said chamber in the plane containing the bottom of the hopper being substantially equal to that of the shaft top portion in said plane.

2. A blast furnace construction comprising a furnace shaft and a at roof therefor, gas offtakes Vwhich emerge from said roof, and a hopper and a bell control therefor for charging into 70 said shaft, the latter having a free area for the passage of gas which constantly increases in size from the level of the bottom of the hopper tothe roof. y

3. A blast furnace roof which is fiat and is comprised of spaced connected upper and lower plates of which the lower plates have heat-insulating material upon their under sides.

4. A blast furnace construction comprising a. furnace shaft and a roof therefor, gas offtakes from the furnace shaft under the roof, and a hopper and a bell control therefor for charging into said shaft, the latter having a free area for the passage of gas which constantly increases in size from the level of the bottom of th hopper to said gas oiftakes and which is of constant size from the bottom of said offtakes to the roof.

5. A blast furnace roof comprised of spaced upper and lower plates, a circular girder connected to and reinforcing said plates, a series of radial girders to which said upper plate is fastened, said radial girders being secured to and extended outwardly from the circular girder, said lower plate having heat-insulating material upon its under side.

6. A blast furn-ace roof comprised of spaced upper and lower plates, a circular girder connected to and reinforcing said plates, a series of radial girders to which said upper plate is fastened, said radial girders being secured to and extended outwardly from the circular girder, in-

ner extensions upon said lower plate, and means 5 for supporting a hopper upon said extensions.

'7. A blast furnace construction comprising a furnace shaft, a hopper and a bell control there-v for for charging into said shaft, the latter having a top portion providing a chamber of constantly l0 vupwardly increasing cross-sectional dimensionsV above the level of the bottom of the hopper.

8. A blast furnace construction comprising a furnace shaft and a roof therefor, gas offtakes adjacent the top of the shaft, and a hopper and l5 a bell control therefor for charging into said shaft, the latter having a free area for the expansion and passage of gas, which free area extends from approximately the level of the bottom of the hopper to said offtakes and is of maximum 20 cross-section Where the offtakes tap the shaft.

KARL F. JUENGLING. 

